Rotary fluid pressure motor, pump, and the like



May 25, 1948. E. H; JOHNSON ROTARY FLUID PRESSURE MOTOR. PUMP, AND THELIKE Filed lay 23; 1944 2 Sheets-Sheet 1 A Home y 1943- I E. H. JOHNSON2,442,130

ROTARY FLUID PRESSURE MOTOR, PUMP, AND THE LIKE Filed May 25, 1944 2Shasta-Sheet 2 l n uenlor W A i Home Patented May 25, 1948 ROTARY FLUIDPRESSURE MOTOR, PUMP, Y AND THE LIKE Edward Harry Johnson, Coventry,England, as-

signor to The Keelavite Company Limited, Allesiey, Coventry, England, acompany of Great Britain Application May 23,1944, Serial No. 536,973 InGreat Britain June 10, 1943 4 Claims.

This invention relates to rotary fluid pressure motors, pumps andthelike, hereinafter termed "rotary engines" for the sake ofconvenience, adapted to operate upon or be operated by fluid whethergaseous or liquid, hereinafter termed the working fluid, and eitheremployed primarily to act upon or be acted upon by the working fluid oremployed as or incorporated in devices such as transmission devices orfluid meters.

The invention is concerned with rotary engines of the kind comprising acasing in which is provided an annular blade chamber, a rotor rotatingabout the axis of the blade chamber and having blades which extendacross the blade chamber through slots in one end wall thereof and makea sealing fit with the inner and outer circumferential walls of theblade chamber and with the end wall hereinafter termed the non-rotatingend wall" remote from that through which they extend, and one or morerotary abutments supported in bearings in a part rigid with the inner orouter circumferential wall of the blade chamber and each extendingacross the blade chamber between inlet and outlet ports and having acircumferential surface which is circular in planes at right angles toits axis of rotation and makes a sealing fit at all times with abutmentrecesses of part-circular cross-section respectively in the inner andouter circumferential walls of w the blade chamber, one or moreblade-receiving recesses being provided in each abutment, each of whichduring rotation of the abutment comes into position to receive a bladeand permit it to pass the abutment as the blade during its rotationcomes to the part of the blade chamber across which the abutmentextends. The capacity of the rotary engine is variable by moving therotor axially together with the non-rotating end wall and thatcircumferential wall of the blade chamher which does not carry theabutment or abutments. Thus the non-rotating end wall moves axiallytowards or away from the rotating end wall to vary the capacity of theblade chamber while the blades slide through the slots in the rotatingend wall so that their effective crosssection is similarly varied.

In such variable capacity rotary engines as previously proposed theinner and outer circumferential surfaces of the rotating end wall and ofthe parts of the blades lying within the slots therein at any time havemade a fluid seal with two non-rotating parts hereinafter termed endwall sealing parts. one of which however is arranged to slide axiallywith the axially movable circumferential wall of the blade chamber so asalways to be in the same axial relationship with the rotating end wall.The other end wall sealing part however is stationary with the resultthat, to maintain a fluid-tight seal at all times around the blade whereit passes through the rotating end wall, the blades must be of the samecrosssection throughout their length otherwise if for example theircircumferential width were reduced towards their ends fluid could escapealong the slots thus left between the blades and the sides of the slotsthrough which they pass and then radially out behind the stationarysealing part referred to when the blades were so far withdrawn from theblade chamber that the portion of reduced width extended outwards beyondthis stationary part.

In rotary engines of the kind referred to increases in the width of theblades necessitates correspondingly larger blade-receiving recesses inthe abutment or abutments which in turn necessitate either reducing thesealing area of the abutment or increasing its diameter for a givensealing area. It is therefore desirable to maintain the width of theblades as small as is possible within the required degree of sealingefflciency and mechanical robustness of the blades. In variable capacityrotary engines of the kind in question however, the blades have to becomparatively long to allow for the required adjustment to vary thecapacity of the engine while to obtain the required mechanicalrobustness especially for the high pressures at which such enginesusually operate, with the present necessity for making the blades of thesame cross-section throughout their effective length, entails making theblades considerably wider than is necessary for sealing purposes orcompatible with compactness.

The object of the present invention is to provide an improvedconstruction of variable capacity rotary engine of the kind referred toin which the above difliculty will be reduced or eliminated.

To this end in a variable capacity rotary engine of the kind referred toaccording to the present invention not only is the axial thickness ofthe rotary end wall suflicient as hitherto to make a fluid seal with atleast a part of the length of the sides of the blades throughout theiraxial movement but the rotary end wall or a part rotating therewithextends radially beyond the circumferential surface of the blade chamberadjacent to the stationary end wall sealing part so that one of thecircumferential surfaces of each blade is sealed by a part rotating withthe rotary end wall and having a face which makes a fluid endof thestationary circumferential wall of the blade chamber. This enablesblades to be employed which are of larger dimensions at the roots wherethey make a fluid-tight seal at their sides with the sides of the slotsin the rotary end wall andvat their circumferential surfacesrespectively with the part rotating with the rotary end wall asexplained above and'with the non-rotating pa which moves axially withthe rotor.

The invention is applicable to rotary engines of thekind referred towherein the rotary abutment or abutments are carried either in the inneror the outer circumferential wall of the blade chamber but forconvenience in the following description it will be described withreference to a construction in which they are carried in the outercircumferential wall.

In this case the inner circumferential wall is arranged-to move axiallywith the rotor and the axially movable end wall may be formed integralwith the inner circumferential wall of the blade chamber. The rotatingend wall is conveniently in the form of a cylinder having a radialthickness equal to the radial dimension of the blade chamber andprovided with longitudinal slots in which the blades slide and fromwhich they project into the blade chamber. In such an arrangement as atpresent made, the end of the cylinder constituting the rotary end wallproper lies and makes a-sealing fit with rotationally stationary parts,theinner one of.which. however,

slides axially with the rotor. When the present invention is applied tosuch a construction the rotary endwall extends radially outwards at theend of the blade chamber beyond the outer circumference thereof and hasan end face making a sealing fit with a corresponding face on theadlacent end of the outer circumferential wall of the blade chamber andan outer circumferential surface which makes a sealing fit with acorresponding fixed circumferential surface. The outward extension ofthe rotating end wall is conveniently constituted by a ring tightlyfitted to the outer circumference of the cylinder constituting therotating end wall and terminating at the blade chamber end approximatelyflush with the end of the cylinder. The blades are then formed so thatfor a certain length from their roots they make a sealing fit with thesides of the slots in the cylinder, with the inner rotationallystationary part and with the ring referred to above while their outerends, which extend into the blade chamber are of reduced width. Thus"the thickened root portions provide a more rigid support for the bladeswhile the construction according to the invention permits this to beemployed without the necessity for retaining the section of the stifferpart throughout the blade length with the consequent increase in weightand size of abutment or reduced abutment sealing area.

The invention may be carried into practice in various ways but oneconstruction according to the invention is illustrated by way of examplein the accompanying drawings, in which Figure 1 is a cross-section of arotary engine according to this invention ina plane passing of the rotorand the comprises a casing A into one end of which exforming with thecasing an annular blade cham-' ber C one end wall C and the innercircumferential wall 0 of which are, formed by the member C while theouter circumferential wall C is constituted by the casing A. The otherend wall of the annular blade chamber (3 is arranged to rotate and isconstituted by the free end of a cylin-. der D formed integral with aflanged hub D rigidly mounted on the driving shaft B.

Mounted in bearings E in the member C is a rotor comprising a hollowshaft E having a flange 'lil formed integral with one end thereof andcarrying two blades 1!: lying in longitudinal slots in the cylinder Dand extending therefrom across the blade chamber C so as to make afluid-tight seal with, the inner and outer circumferential walls and theend wall C thereof. The hollow shaft E carries within it a bearingengaged by the end of an extension B" of the shaft B.

' Mounted to rotate within the casing about an axis parallel to that ofthe rotor is an abutment G disposed between inlet and outlet ports (notshown) in the blade chamber and. making a sealing fit at all times withabutment recesses respectively in the inner and outer circinnferentialwalls of the blade chamber in known manner and provided withblade-receiving recesses adapted to receive the blades as the rotor andthe abutment rotate in synchronism when these blades come to the part ofthe blade chamber across which the abutment extends and thus permit theblades to pass the abutment. The synchronised rotation of the rotor andabutment is effected by gear wheels H and H secured respectively to therotor shaft E and the shaft G of the abutment G, and arranged to permitthe axial movement of the member C with the rotor.

The part C of the member C which constitutes the inner circumferentialwall of the blade chamber extends within the free end of the cylinder Dso as to make a fluid-tight Joint with its inner circumferentialsurface, while a ring J surrounds the cylinder D closely so as to make asealing fit with the outer circumferential surfaces of the blades. Theend of this ring J adjacent to the blade chamber also makes a fluid sealwith the surface J extending radially outwards from the end of the bladechamber and with the length of the ring J being sufficient to maintainthis seal throughout the axial movement of the member C and the rotor.The free ends of the blades, however, where they extend into the bladechamber are narrower as shown at E Thus while the root portions providea rigid support for the effective parts E of the blades, these parts canbe relatively narrow and only of such width as is dictated byconsiderations of fluid sealing and rigidity bearing in mind their shortunsupported length compared with blades of similar width throughouttheir entire length as was previously necessary in order to maintain thenecessary fluid sealing.

The outer circumferential surface of the ring J makes a fiuid seal ashown with a plate K rigidly mounted within the casing A.

What I claimas my invention and desire to secure by Letters Patent is:

1. A variable capacity rotary engine including in combination a casing,a rotor arranged to be movable axially within the casing and comprisinga support and blades extending axially therefrom, an annular bladechamber having inlet and outlet parts and into and across which theblades extend and comprising inner and outer circumferential walls oneof which is rigid with the casing while the other circumferential wallcan move axially with the rotor, and end walls one of which rotates withthe rotor and has slots therein through which the blades project intothe blade chamber while the other end wall, with which the ends of theblades make a sliding fit, is fixed rotationally but movable axiallywith the rotor, abutment recesses of part-circular crosssection in theinner and outer circumferential walls, and at least one rotary abutmentsupported in bearings in a part rigid with the casing, extending acrossthe blade chamber between the inlet and outlet ports and having acircumferen- 1 tial surface making a sealing fit at all times withrotary end wall not only has an axial thickness sufficient to make afluid-tight seal with the root portion throughout the axial movement ofthe blades through the slots in the said rotary end 'wall but also has apart which extends radially beyond the circumference of the fixedcircumferential surfaces of each blade to provide a surface making afluid-tight seal with a corresponding surface on the adjacent end of thestationary circumferential wall of the blade chamber.

2. A variable capacity rotary pump including in combination a casing, arotor arranged to be movabl axially within the casing and comprising asupport and blades extending axially therefrom, the circumferentialwidth of the root porhas slots therein from which the blades extendacross the blade chamber and with which the sides of the root portionsonly of the blades make a sealing fit while the other end wall, withwhich the ends of the blades make a sliding fit, is fixed.

rotationally but slides axially with the rotor, abutment recesses ofpart-circular cross-section in the inner and outer circumferentialwalls, at

least 'one rotary abutment supported in bearings in a part rigid withthe outer circumferential wall of the blade chamber, extending acrossthe V blade chamber between inlet and outlet ports and having acircumferential surface making a 7 sealing fit at all times with theabutment recesses, at least one blade-receiving recess being provided ineach abutment which during rotation comes into position to receive ablade and permit it to pass the abutment, and an annular part rigid withthe rotary end wall and extending radially outward adjacent to the endof the blade chamber where not only does a surface on the said annularpart make a sealing fit with a corresponding face on the end of theouter circumferential wall of the blade chamber, but it provides acircumferential wall with which the outer circumferential surface ofeach blades makes a sealing fit. I

3. A variable capacity rotary engine having the combination of elementsclaimed in claim 2, in which the annular part is constituted by a ringcloselysurrounding and rigidly mounted on the outer circumference of thecylinder constituting the rotary end wall of the blade chamber;

4. In a variable capacity rotary engine comprising a casing providing anouter circumferential wall of an annular working chamber, a rotormounted in the casing for axial as well as rotary motion, and an annularmember mounted within the casing for axial movement with the rotor andfixed against rotation relative to the casing, the said annular memberproviding an inner circumferential wall and one end wall of the annularworking chamber, the combination of a cylindrical member mounted withinthe casing for rotation with the rotor and fixed against axial movement,the said cylindrical member 1 tion of each of which blades is greaterthan that having an edge that provides a second end wall for the workingchamber and the said cylindrical member being provided with slots thatregister with the chamber in axial alignment therewith, blades mountedon the rotor and comprising root portions slidably engaged within theslots of the cylindrical member and piston portions of lesser thicknessthan the root portions and that extend through the working chamber andslidably contact. the circumferential and first end walls thereof, and asealing ring surrounding and secured to the cylindrical member andslidably engaging the outer surfaces of the portions of the bladeswithin the slots of the said cylindrical member, the said ring extendingaxially from the wall-forming edge of the cylindrical member at least asfar along the said cylindrical member as the position which can bereached by the inner ends of the root portions of the blades, and havinga surface slidably engaging the casing to form a sealing contact withthe outer circumferential wall structure of the chamber.

EDWARD HARRY JOHNSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,994,391 Loveridge et a1. Mar.12, 1935 2,258,504 Booth .Oct. 7,1941

FOREIGN PATENTS Number Country Date 448,952 Great Britain June 18, 1936

